In addition to ThreePhaseEel's excellent answer about boxes and splices, there may be an additional problem: Required receptacles.
There are many required receptacles, including (but probably not limited to):
- One every 12' on most walls in finished spaces. It gets a little tricky around doors and there are various exceptions.
- One every 4' around kitchen counters. It gets a little tricky around built-in appliances, islands, peninsulas, etc. and there are various exceptions.
- Two required kitchen circuits. So if you remove the last receptacle of one of the circuits you have a problem.
- Required bathroom circuit. Can be shared with other bathrooms, but the receptacle has to be there, and within certain parameters - near the sink, but not too close to the tub/shower, etc.
- Required laundry room circuit.
If all those (and any similar) requirements are not a problem then you can remove the receptacle. However, there are three reasons why you might be removing the receptacle:
- Aesthetics - paint or wallpaper or whatever the blank plate to match the rest of the wall and you'll hardly notice it.
- Non-permanent stuff - e.g., movable furniture. No problem.
- Permanent stuff - e.g., kitchen cabinets, built-in bookcases, etc.
This last situation is a real problem. You can't block a live junction box with permanent fixtures whether it has a receptacle, a switch or just a blank plate. So if that is the situation then you may have to reroute wires/cables, which may be very simple or may be very complicated, depending on the specifics.